Electrically driven metronome



,March 21, 1939. F. FRANZ 2,150,967

ELECTRICALLY DRIVEN METRONOME Filed Jan. 25, 1937 2 Sheets-Sheet 2 Patented Mar. 21, 1939 UNITED STATES PATENT OFFICE 16 Claims.

This invention relates to tempo-indicating-devices, and more particularly to a device of this character usually known as a metronome in that it is provided with means to effect audible signals or beats at a certain time rate or interval, which rate may be varied according to the desire of the user of the device.

More particularly the invention consists in a device of this character which may be electrically operated so that the rate of speed or the time interval at which it is set will always be constant for that particular setting, and other advantages reside in the fact that no operating spring is required, as is the case in the usual spring motor, and any winding of such a spring is, of course, eliminated.

One object of the invention is the: pro-vision of an electrically driven timing device such as a metronome, which may beset to give audible signals at any desired time interval.

A still further object of the invention is the provision of a device of this character which may be of simple construction and which at the same time may have advantages in operation over devices of this character now in use.

A still further object of the invention is the provision of an electrically operated metronome which may be set or regulated to give audible signals at any desired time interval, and so arranged that the variation in the number of signals given in any unit of time may be varied simply and easily by means of a pointer movable over a scale, the mechanism. being so arranged that a relatively greater movement of the pointer is necessary to effect changes. of a given degree when the signal is given at a slower rate than when the signal is given at a faster rate.

To these and other ends the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

In the drawings:

Fig. 1 is a side elevational view of a metronome embodying my improvements, the case being broken away to show the interior mechanism;

Fig. 2 is a horizontal sectional view through the case showing the operating mechanism in top plan view;

Fig. 3 is a sectional view on line 3-3 of Fig. 1 showing the operating mechanism in end elevation;

Fig. 4 is a view similar to Fig. 1 showing a modified form of my device; and

Fig. 5 is a diagrammatic view showing a further modification.

To illustrate a preferred embodiment of my invention, I have shown in Fig. 1 a case I having a bottom or base portion II upon which the case is designed to rest, and which forms a support for the operating parts of the device. Suitably supported from the base II are upstanding brackets l2 and I3 connected together adjacent their upper ends by straps l4 and I5.

To the strap I4 is connected the field structure E6 of a suitable electric motor. The motor is provided with a rotor I1 having a shaft 18 which extends between the brackets l2 and I3 and carries the driving pinion [9. The flow of electric current to the motor may be controlled in the usual manner by the switch 20 mounted upon one end of the case so as to be conveniently manipulated by the user of the device from the outside of the case.

Rotatably mounted in the straps M and I is a shaft 2| having secured thereon a gear 22, the teeth of which mesh with the teeth of the pinion l9, It will be noted that this pinion is of somewhat greater width than that of the gear, and the shaft 2| is shiftable longitudinally to some extent in its bearings in the straps l4 and I5, and is urged toward the right, as shown in Figs. 1 and 2, by the leaf spring 23 secured to the strap M at one end and having its free end bearing against the shaft 2|.

Secured upon the shaft 2| to rotate therewith is a driving member 24. This member may be given a number of different forms. Certain advantages arise from the preferred form which I have illustrated. This member is preferably a frictiondriving member, and the driving surface is that of a modified conical surface having the shaft 2| as its axis. The elements of the cone surface, however, instead of being straight lines, are preferably curved, and in this case are in the shape of arcs of a circle drawn about a radius lying without the shaft 2i. The driving surface of this member may be considered as being a surface generated by the revolution about the axis 2| of the arc of a circle having its center at some point without the shaft.

Each of the standards [2 and I3 is provided with a depending ear portion 26, to which ear portions is pivoted a rectangular frame comprising side members 21 and end members or straps 28, this frame being pivoted to the cars 26 at 29, so that it is swingable about the line joining the two points 29 in the opposite ears 26 as an axis. It may here be stated that in the present em bodiment of my invention a point upon this axis is also the center of the are forming one of the elements of the driving member 24.

Rotatably mounted between the members 21 is a shaft 30 carrying a driven member 3| diskshaped in form, as illustrated, the edge of this member being adapted to contact frictionally with the curved driving surface of the member 24, the contact being at the point 32, shown in dotted lines in Fig. 1, whereby this disk is rotated upon rotation of the driving member 24. It will be apparent that, as the rectangular frame carrying the disk 3| is swung about its pivotal points 29, the disk will be moved over the surface of the driving member 24 so as to vary the position of the contact point 32, and that the speed with which the disk 3| is driven will be varied depending upon the distance of this point of contact from the shaft 2| carrying the driving member 24. This results from the fact that the peripheral speed of the disk 3| will be the same as the velocity of the point of the driving member 24 with which the disk is in contact. As shown, the point 32 is adjacent the extreme outer edge of the driving member 24, and therefore adjacent the point farthest from the shaft 2|. As this point on the driving member 24 will have the greatest speed of any point on this member, the disk 3| will be driven at maximum speed. When the edge of the disk 3| adjacent the driving member 24 is moved upwardly, as shown in Fig. 1, the point of contact 32 will be at a lesser distance from the shaft 2|, or will be at a point on the surface of the driving member having a smaller radius, and therefore such point will rotate at a slower linear speed, and therefore drive the disk 3| at a slower speed. As the disk 3| is swung about or pivoted upon an axis which passes through the center of the arc forming an element of the driving mem ber 24, it will be seen that the edge of the disk may be moved across the surface of the driving member without making any substantial change in the position of the driving member. Any variations in this respect, however, will be taken care of by the fact that the shaft 2| is mounted for limited longitudinal movement in its bearings, and the driving member 24 will always be urged against the disk by the spring 23.

Mounted upon the shaft 30 is a cam member 33 the surface of which engages the end of an arm 34 secured to a post 35 mounted to rock in extensions 36 and 31 of the members 21. Also secured to this post is a beater or hammer arm 38 carrying a hammer 33 designed to strike the side of the case ID to give audible beats or signals. This hammer is designed to project through an opening 40 in the plate l3, so as to be permitted to contact with the case.

A spring 4| is mounted upon the post 35, and one end of this spring acts against the arm 34 so as to maintain it in contact with the surface of the cam 33, while the other end reacts against the end member 28 of the pivoted rectangular frame which carries the shaft 30 and disk 3|.

It will be noted that the striker or hammer 39, together with its associated parts, the disk 3| and cam 33, are all carried by the swinging rectangular frame so that movement of this frame to vary the driving speed relation of the disk 3| and driving member 24 does not disturb the relationship of any of these parts. Movement of this frame does vary the point of contact of the hammer 39 with the case, and for this purpose the slot 40 is somewhat elongated and arc-shaped, as shown in Fig. 1, so as to permit movement of the hammer when the frame is swung about its pivot, and still provide for the hammer striking a part of the case.

Secured to one end member 28 of the rectangular frame is an actuating arm 43, which extends through a slot 44 in one side of the case, and terminates in a pointer 45 adapted to cooperate with a scale 43 provided upon the side of the case. This movement of the arm 43, which is rigidly se cured to the rectangular frame carrying the drlven disk 3|, will swing this frame about its pivots and change the driving speed relationship between the disk and the driving member 24, which change will be correctly indicated by the pointer 43 and scale 46. That this pointer will indicate upon the scale the number of beats per unit of time of the hammer or striker 39.

It will be apparent that the speed of the disk 3| will not vary uniformly as it is moved over the surface of the driving member 24, but that a given movement of this disk will effect a greater change in its velocity adjacent the outer portion of the driving member 24 than would be effected by thesame movement of the disk when in contact with the surface of the driving member in proximity to the shaft 2|. This is of advantage in the operation of the device, for, when the disk 3| is operating at slower speeds, it is desirable to obtain finer variations in its speed than when it is operating at higher speeds, and therefore it is of advantage that a greater movement of the disk is necessary to effect a given change in its speed when it is running slowly than when it is operating at a higher speed. In other words, when the striker is delivering beats in the range of 40 to per minute, it may be desirable to eifect changes of two beats per minute, while when the striker is operating at 150 to 200 beats per minute, it is usually only desirable to change the speed in steps of eight beats per minute, and the present arrangement provides, therefore, for a greater movement of the pointer 45 to effect a given change at the low-tempo end of the scale than at the high-tempo end.

It will be apparent that as the disk 3| rotates, the arm 34 will travel over the eccentric surface of the cam 33, and the hammer 39 will be moved away from the case until the end of the arm 34 rides over the high point of the cam and drops over the stepped surface 4'5, when the hammer will be driven against the case by the spring 4|, the hammer delivering one beat for each revolution of the disk 3|. If more than one beat is desired, the shape of the cam 33 may, of course, be changed accordingly.

In the form of my invention shown in Figs. 1 to 3, the driving member 26 is provided upon a countershaft driven by the speed reducing gear 22 and pinion on the motor shaft. This provides for the driving of the shaft 2i at a slower speed than that of the motor shaft. It is possible, however, to secure a motor of a sufficiently slow speed such that no speed-reducing gearing is necessary, and in such case the counter-shaft may be omitted, as is illustrated in the modified form of my invention shown in Fig. 4. As illustrated in this figure, an electric motor 50 is secured in any suitable manner to standards 6| and 32 resting upon the base II of the case it. The field of this motor is shown at 53, and carries a strap 64 within. which is secured an arbor upon which is rotatably mounted the driving member 66 having bearings upon the arbor at E7 and E8. Secured to this driving member is the motor armature 69 rotatable within the field.

The driven disk 3| and associated parts may be constructed like the corresponding parts described in connection with Figs. 1 to 3 of the drawings. It will be noted, however, that in this instance the disk Bi is placed in a slightly inclined position when in contact with the lower end of the driving member 65, so that this driving member will receive vertical support from this disk, as the armature and driving member are free to move vertically upon the arbor Frictional contact between the driving member 66 and the disk 36 will, therefore, be maintained by the weight of the driving member and motor armature. It may be desirable in a construction of this kind to arrange the center of the armature in a plane slightly above the center of the field flux, so that, when the motor is in operation, there will be a slight downward pull by the flux upon the armature and driving men ber t6 to assist the Weight of these members in maintaining frictional driving relation with the disk 3!. The operation of this device substantially the same as that of the device shown in Figs. 1 to 3, and no additional description will be necessary. It will be apparent, however, that in this case the driving member is mounted directly upon the motor shaft or rotor, and no countershaft is necessary. In this instance, also, the driving member is so shaped that a greater movement of the disk required for a given change of speed of this disk at the lowtempo end of the scale than at the high-tempo end.

In Fig. 5 of the drawings I have shown diagrammatically a further modification of my device. In this case a motor is represented at it having a shaft it provided'with a driving member '52 in frictional driving relationship with a member 13 of spherical form. Contacting with the inner surface of the m mber '53 is a driven member l lin the form of a disk, this member being carried in a rocking frame '65 so that it may be swung over the surface of the driving member it to vary the distance of its point of contact there-with from the axis '56 of the mem ber '53. The driven disk M is provided with a in Tl adapted to strike one end of a hammer l8 pivoted at it so as to produce strokes of the hammer against cooperating surface, not shown. It will, of course, be understood that the hammer will be so arranged as to swing with the disk T l. As the operation of this device is quite similar to those modifications already described, it will be understood without further description.

While I have shown and described some preferred embodiments of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the appended claims.

What I claim is:

1. A metronome comprising a rotatable driv ing member, a rotatably mounted driven member having operative frictional engagement with said driving member, said driven member being swingably mounted to vary its point of engagement with said driving member and thereby vary the speed at which it is driven, a striker operated by said driven member in any position thereof, said striker being movable with the driven member in its swinging movement, and a sounding board, against which the striker strikes, presenting surface substantially parallel to the plane of such swinging movement of the striker.

2. A metronome comprising a rotatable driving member, a driven member having operative frictional engagement with the driving member,

mounting means in which said driven member is rotatably mounted, means for moving said mounting means to change the point of engagement of said driving and driven members and vary the speed of the latter, a striker actuated by the driven member, said striker being movable with the mounting means, and a sounding board, against which the striker strikes, presenting a surface substantially parallel to the plane of movement of said mounting means.

3. A metronome comprising a rotatable driving member, a driven member having operative frictional engagement with the driving member, mounting means in which said driven member is rotatably mounted, said mounting means being pivotally supported to move about an axis transverse to the axis of the driving member whereby movement thereof moves said driven member to varsits: point of engagement with the driving member, a striker member carried by said mounting means and actuated by the driven member, means to move said mounting means, and indicating means to indicate the rate of operation of said striker member.

s. A metronome comprising a rotatable driving member having a tapering siuface circular in crosssection in a plane normal to the axis of rotation, a rotatable driven member having its edge frictionally engaged with said surface to be driven thereby, said driven member being mounted for swinging movement over the surface of said driving member about an axis lying in the plane of the driven member to vary its point of engagement therewith and thereby vary the speed of the driven member, and. a sounding device actuated by said driven member, said swinging movement taking place about an axis transverse to the axis of rotation of the driving member whereby a greater movement of said driven member is required to produce a given change of speed in the lower speed ranges than in the highor speed ranges.

5. A. metronome comprising a casing having therein a rotatable driving member having a tapering surface circular in cross-section in a plane normal to the axis of rotation and longitudinally curved, a rotatable driven member having its edge frictionally engaged with said surface to be driven thereby, said driven member being mounted for swinging movement over the surface of said driving member about an axis lying in the plane of the driven member to vary its point of engagement therewith and thereby vary the speed of the driven member, a striker in said casing, and means actuated by said driven member and connected to said striker to move the same.

6. A metronome comprising a casing having therein a motor, a sounding device, means for operating the sounding device from the motor comprising a change speed mechanism, and movable means extending without the casing for effecting speed changes through said mechanism, said means requiring a greater movement to effeet a given change of speed in the lower speed ranges than in the upper speed ranges, and a scale with which said means cooperates to indicate the rate of operation of the sounding device.

7. A metronome comprising a rotatable driving member, a driven member having operative engagement with said driving member to be driven thereby, a striker actuated by the driven member, movable means for varying the driving speed relationship of said driving and driven members, and said means requiring a greater movement for a given change of speed at a lower range of speed than at a higher range.

8. A metronome comprising a rotatable driving member, a disk-shaped driven member having operative frictional engagement; with said driving member, pivotally mounted means supporting said driven member whereby said supporting means may be swung about an axis transverse to the axis of the driving member to vary the point of engagement of the driving and driven members, a striker mechanism carried by said supporting means, said mechanism comprising a striker and a striker-actuating member operated by said driven member, and means against which said striker impinges to effect andible signals.

9. A metronome comprising a casing having therein a rotatable driving member, a diskshaped driven member having operative frictional engagement with said driving member, pivotally mounted means supporting said driven member and movable about an axis transverse to the axis of the driving member to vary the point of engagement of the driving and driven members, said driving member having a concave conical surface curved about the axis of said mounting means as a center, and a striker mechanism carried by said mounting means, said striker mechanism comprising a pivoted striker member and an arm actuated by the driven member and connected to the striker member to move the same.

10. A metronome comprising a rotatable driving member, a disk-shaped driven member having operative frictional engagement with said driving member, said driven member being mounted to rotate on a tiltable axis whereby it may be moved to vary its point of engagement with the driving member, and a pivoted striking mechanism having a striker member and an arm extending from its pivot, and means actuated by the driven member to engage said arm and effect movement of the striker.

11. A metronome comprising a rotatable driw ing member, a disk-shaped driven member having operative frictional engagement with said driving member, said driven member being mounted to rotate on a tiltable axis lying in a common plane with the axis of the driving member whereby it may be moved to vary its point of engagement with the driving member, and a pivoted striking mechanism having a striker member and an arm extending from its pivot, and cam means operated by the driven member to engage said arm and actuate the striker.

'12. A metronome comprising a rotatable driving member, a driven member having operative frictional engagement with the driving member, mounting means in which said driven member is rotatably mounted, means for moving said mounting means about an axis transverse to the axis of the driving member to change the point of engagement of said driving and driven members and vary the speed of the latter, and a striker member carried by the mounting means and actuated by the driven member.

13. A metronome comprising a rotatable driving member, a disk-shaped driven member having operative frictional engagement With said driving member, said driven member being mounted to rotate on a tiltable axis whereby it may be moved to vary its point of engagement with the driving member, and a striking mechanism comprising a. striker member and a part actuated by said driven member and connected to the striker member to actuate the same.

14. A metronome comprising a motor having a rotor rotatable on a substantially vertically dis posed axis, a driving member on the lower end of the rotor having a downwardly facing tapering driving surface, a driven disk having its edge in contact with said surface, mounting means upon which the disk is rotatably mounted, said mounting means being pivotally movable about an axis transverse to the axis of the driving member, and a striker carried by the mounting means and actuated by the driven disk.

15. A metronome comprising a motor having a rotor rotatable on a substantially vertically disposed axis, a driving member on the lower end of the rotor having a downwardly facing tapering driving surface, a. driven disk having its edge in contact with said surface, mounting means upon which the disk is rotatably mounted, said mounting means being pivotally movable about an axis transverse to the axis of the driving member, and a striker carried by the mounting means and actuated by the driven disk, and said rotor being free for limited movement in the direction of its axis.

16. A metronome comprising a motor having a rotor rotatable on a substantially vertically disposed axis, a driving member on the lower end of the rotor having a downwardly facing tapering driving surface, a driven disk having its edge in contact with said surface, mounting means upon which the disk is rotatably mounted,

said mounting means being pivotally movable about an axis transverse to the axis of the driving member, and a striker carried by the mounting means and actuated by the driven disk, said rotor being free for limited movement in the direction of its axis, and said driving member being urged into contact with the driven disk.

FREDERICK FRANZ. 

